The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
In automotive transmission art, the dual clutch transmission (DCT) is a relatively new concept. A typical dual clutch transmission configuration includes a pair of mutually exclusively operating input clutches which drive a pair of input shafts. The input shafts may be disposed on opposite sides of an output shaft or may be disposed concentrically between spaced-apart output shafts. One of each of a plurality of pairs of constantly meshing gears which provide the various forward and reverse gear ratios is freely rotatably disposed on one of the shafts and the other of each pair of gears is coupled to one of the other shafts. A plurality of synchronizer clutches selectively couple the freely rotatable gears to the associated shaft to achieve forward and reverse gear ratios. After the synchronizer clutch is engaged, the input clutch associated with the input shaft having the engaged synchronizer clutch is applied to transmit power through the transmission. Reverse gear is similarly achieved except that it includes an additional (idler) gear to provide torque reversal.
Dual clutch transmissions are known for their sporty, performance oriented operating characteristics which mimic those of a conventional mechanical (manual) transmission. They also typically exhibit good fuel economy due to their good gear mesh efficiency, ratio selection flexibility, reduced clutch losses and lack of a torque converter.
Control of the input clutches and selection and engagement of a particular gear by translation of a synchronizer and associated positive clutch is typically achieved by a hydraulic control system which is supplied with a flow of pressurized hydraulic fluid from a dedicated hydraulic fluid supply system. Optimum performance and operating efficiency can be achieved by utilizing active flow and pressure regulators in the hydraulic fluid supply system such that the hydraulic control system exhibits low leakage and positive and highly repeatable control and shift characteristics. The present invention is so directed.